Rename Gateway MCP product tools to a gateway_ prefix (major) #352

Why

The Event Gateway MCP server names its tools hookdeck_connections, hookdeck_sources, hookdeck_events and so on. These are Gateway resources wearing a platform prefix.

That was fine when there was one MCP server. There are now two, and the naming no longer distinguishes what it needs to:

• outpost_tenants — an Outpost resource, correctly prefixed
• hookdeck_connections — a Gateway resource, prefixed as though it were platform-level

Configure both servers in one client, or build the top-level server in #351, and an agent cannot tell from the name which product a tool belongs to.

Proposal

Rename Gateway's product tools to a gateway_ prefix:

hookdeck_connections     -> gateway_connections
hookdeck_sources         -> gateway_sources
hookdeck_destinations    -> gateway_destinations
hookdeck_transformations -> gateway_transformations
hookdeck_requests        -> gateway_requests
hookdeck_events          -> gateway_events
hookdeck_attempts        -> gateway_attempts
hookdeck_issues          -> gateway_issues
hookdeck_metrics         -> gateway_metrics
hookdeck_help            -> gateway_help

Platform tools keep the hookdeck_ prefix in every server, because that is what they are — you log into Hookdeck and switch Hookdeck projects, not Outpost or Gateway ones:

hookdeck_login     (unchanged in Gateway; Outpost renamed to match)
hookdeck_projects  (unchanged in Gateway; Outpost renamed to match)

The rule: product tools take the product prefix, platform tools take hookdeck_.

Version impact: MAJOR

This is a MAJOR bump under the SemVer table in .agents/skills/hookdeck-cli-release/SKILL.md ("requires users to change scripts, configs, or habits").

It is worth being precise about how it does and does not break, because an MCP contract is not an API contract:

Does not break: tool discovery is entirely runtime. Agents call tools/list and use what is there. There is no pinned client library and no compile-time binding, so nothing stops working the way a removed HTTP endpoint would. Hookdeck's own published agent skills reference zero MCP tool names, so they are unaffected.

Does break, and this is the sharp edge: clients grant permissions per tool name. Claude Desktop remembers approvals per tool; Claude Code has --allowedTools. After a rename, existing approvals do not carry — at best the user is re-prompted, at worst a strict allowlist silently omits the tool. Silent unavailability is the failure worth warning about.

Degrades softly: stored prompts, CLAUDE.md files and team runbooks that name tools. Models adapt, but quality dips.

Release notes must call out that per-tool approvals and any allowedTools config need updating.

Shares a major with

• #340 — errors move from stdout to stderr
• #347 — removing the JSON form of gateway --config

Three contract changes now queued for the same major, which makes a single v3.0.0 "contract release" worth planning rather than three independent deferrals that each drift.

Related

• #351 — the top-level server, where prefixes become load-bearing